Summary
This phase III trial compares the addition of rucaparib to enzalutamide with enzalutamide alone for the treatment of men with prostate cancer that has spread to other places in the body (metastatic) and has become resistant to androgen-deprivation therapy. Testosterone is a hormone made mainly in the testes and is needed to develop and maintain male sex characteristics, such as facial hair, deep voice, and muscle growth. It also plays role in prostate cancer development. Enzalutamide may help fight prostate cancer by blocking the use of testosterone by the tumor cells for growth. PARPs are proteins that help repair deoxyribonucleic acid (DNA) mutations. PARP inhibitors, such as rucaparib, can keep PARPs from working, so tumor cells can't repair themselves. This may stop tumor cells from growing. Giving enzalutamide and rucaparib may prolong patients’ survival and/or prevent their cancer from growing or spreading for a longer time. It may also help doctors learn if a mutation in any of the specific DNA repair (homologous recombination) genes is helpful in selecting the most appropriate treatment for the patient.